1. Field of the Invention
The invention relates to an adapter base for receiving electronic test objects (DUT=device under test), which has an outer group (array) of contact pins led through from its top side to the underside, and also an inner matrix of contacts which are led out only on the underside and to which a region free of circuitry corresponds on the top side.
2. Discussion of the Prior Art
In order to test objects, in particular compact electronic components having a multiplicity of terminals, it is known to clamp these fixedly on a zero insertion force base (ZIF=Zero Insertion Force) which is fixedly connected to a board by its contacts projecting on the underside. The difficulty is that the configuration of the object to be tested varies within a series or from manufacturer to manufacturer, so that only by expending effort and devoting a great deal of time is it possible for the integrated circuit that is to be tested to be connected up in accordance with the requirements. only with the aid of an individually produced transition circuit is it possible for electrical signals and supply voltages to be allocated correctly to the individual contacts.
The invention is based on the object of remedying this and providing an adapter base for receiving electronic test objects which, within an extremely short time, for all the contact pins simultaneously ascertains the electrical contact of the integrated circuit to be tested and performs automatic switching at the contact pins in accordance with the object to be tested, to be precise depending on whether the contact pins are intended to transmit electronic signals or serve as supply contacts.
In the case of an adapter base of the design explained in the introduction, this object is achieved according to the invention by virtue of the fact that each contact pin is connected to a series circuit which is formed in the adapter and comprises a switching transistor and at least one capacitor which, by means of a control signal, can be connected in and disconnected by the gate of the switching transistor, said gate being connected to an assigned contact on the underside.
The fact that each contact pin is connected to additional electronic components (switching transistor and capacitor) affords the possibility, depending on the required operating mode of the contact pin, of transmitting signals or connecting the contact pin to operating voltage or ground. By means of a control signal supplied by a control unit, e.g. computer or PC, the gate of the switching transistor is opened or closed, so that the capacitor is connected in as required.
It is advantageous if two capacitors having different capacitances are provided.
In another embodiment of the invention, the contact pins are designed as spring pins, which ensure a reliable connection between the soldering lands of the board accommodating the components to be tested and the contacts of the adapter base.
If the adapter base has a multilayer hybrid structure, a highly compact design is possible which allows a multiplicity of components to be accommodated in the base. Thus, it is possible for instance to accommodate 225 transistors and 500 capacitors, for example, in a plurality of layers.